277 research outputs found
Higgs portal vector dark matter for GeV scale γ-ray excess from galactic center
We show that the GeV scale γ-ray excess from the direction of the Galactic Center can be naturally explained by the pair annihilation of Abelian vector dark matter (VDM) into a pair of dark Higgs bosons (VV→ ϕ ϕ), followed by the subsequent decay of ϕ into bb̄ or τ τ̄ . All the processes are described by a renormalizable VDM model with the Higgs portal, which is naturally flavor-dependent. Some parameter space of this scenario can be tested at the near future direct dark matter search experiments such as LUX and XENON1T
Hidden sector monopole, vector dark matter and dark radiation with Higgs portal
We show that the 't Hooft-Polyakov monopole model in the hidden sector with Higgs portal interaction makes a viable dark matter model, where monopole and massive vector dark matter (VDM) are stable due to topological conservation and the unbroken subgroup U(1 X. We show that, even though observed CMB data requires the dark gauge coupling to be quite small, a right amount of VDM thermal relic can be obtained via s-channel resonant annihilation for the mass of VDM close to or smaller than the half of SM higgs mass, thanks to Higgs portal interaction. Monopole relic density turns out to be several orders of magnitude smaller than the observed dark matter relic density. Direct detection experiments, particularly, the projected XENON1T experiment, may probe the parameter space where the dark Higgs is lighter than ≲ 50 GeV. In addition, the dark photon associated with the unbroken U(1 X contributes to the radiation energy density at present, giving Δ Neffν ∼ 0.1 as the extra relativistic neutrino species
Elliptic genera of monopole strings
We obtain elliptic genera of monopole string in 5d MSYM. We find agreement with the corresponding TST-dual dyonic-instanton single particle indices in arXiv:1110.2175 . We make use of (2,2) superconformal algebra and its spectral flow, and the agreement can therefore be taken as evidence that monopole string (4,4) sigma models are exactly quantum superconformal
The geometric Langlands twist in five and six dimensions
Abelian 6d (2,0) theory has SO(5) R symmetry. We twist this theory by identifying the R symmetry group with the SO(5) subgroup of the SO(1,5) Lorentz group. This twisted theory can be put on any five-manifold M, times R, while preserving one scalar supercharge. We subsequently assume the existence of one unit normalized Killing vector field on M, and we find a corresponding SO(4) twist that preserves two supercharges and is a generalization of the geometric Langlands twist of 4d SYM. We generalize the story to non-Abelian gauge group for the corresponding 5d SYM theories on M. We derive a vanishing theorem for BPS contact instantons by identifying the 6d potential energy and its BPS bound, in the 5d theory. To this end we need to perform a Wick rotation that complexifies the gauge field
Multi-faced black Janus and entanglement
To the second order of the deformation parameter, we construct the black brane solutions, which are dual to the multiple interface deformations of conformal field theories. We compute their thermodynamic quantities from the gravity and the field theory sides, and find a precise agreement, confirming the validity of the AdS/CFT correspondence. The correlation of two separate interfaces induces a Casimir energy and an interesting form of correlated entropy contribution. We comment on the properties of the interface lattice system too
A three-loop neutrino model with global U(1) symmetry
We study a three-loop induced neutrino model with a global U(1) symmetry at TeV scale, in which we naturally accommodate a bosonic dark matter candidate. We discuss the allowed regions of masses and quartic couplings for charged scalar bosons as well as the dark matter mass on the analogy of the original Zee–Babu model, and show the difference between them. We also discuss that the possibility of the collider searches in a future like-sign electron liner collider could be promising
Renormalization group-induced phenomena of top pairs from four-quark effective operators
We study the renormalization group(RG) evolution of four-quark operators that contribute to the top pair production. In particular, we focus on the cases in which certain observables are first induced from the one-loop RG while being absent at tree-level. From the operator mixing pattern, we classify all such RG-induced phenomena and underlying models that can induce them. We then calculate the full one-loop QCD RG evolution as the leading estimator of the effects and address the question of which RG-induced phenomena have largest and observable effects. The answer is related to the color structure of QCD. The studied topics include the RG-induction of top asymmetries, polarizations and polarization mixings as well as issues arising at this order. The RG-induction of top asymmetries is further compared with the generation of asymmetries from QCD and QED at one-loop order. We finally discuss the validity of using the RG as the proxy of one-loop effects on the top pair production. As an aside, we clarify the often-studied relations between top pair observables
Search for a doubly-charged boson in four-lepton final states in type II seesaw
CMS and ATLAS have searched for a doubly-charged boson <math altimg="si1.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msup><mrow><mi>H</mi></mrow><mrow><mo>±</mo><mo>±</mo></mrow></msup></math> which may arise from type II seesaw in the 7 TeV run at the LHC by considering pair or associated production of doubly-charged bosons under the assumption of degenerate triplet scalars. In this work, we consider non-degenerate triplet components with the mass gap <math altimg="si2.gif" xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Δ</mi><mi>M</mi><mo>∼</mo><mn>1</mn><mtext>–</mtext><mn>40</mn><mtext> GeV</mtext></math> which leads to enhanced pair-production cross-sections of <math altimg="si1.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msup><mrow><mi>H</mi></mrow><mrow><mo>±</mo><mo>±</mo></mrow></msup></math> added by the gauge decays of the heavier neutral and singly-charged bosons. We reevaluate the constraints in the Δ M – <math altimg="si3.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow><mi>M</mi></mrow><mrow><msup><mrow><mi>H</mi></mrow><mrow><mo>+</mo><mo>+</mo></mrow></msup></mrow></msub></math> plane depending on the triplet vacuum expectation value <math altimg="si4.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow><mi>v</mi></mrow><mrow><mi mathvariant="normal">Δ</mi></mrow></msub></math> in the type II seesaw model which are much more stringent than the current search limits. We further study the possibility of observing same-sign tetra-lepton signals in the allowed parameter space which can be probed in the future runs of the LHC
Abelianization of BPS quivers and the refined Higgs index
We count Higgs “phase” BPS states of general non-Abelian quiver, possibly with loops, by mapping the problem to its Abelian, or toric, counterpart and imposing Weyl invariance later. Precise Higgs index computation is particularly important for quivers with superpotentials; the Coulomb “phase” index is recently shown to miss important BPS states, dubbed intrinsic Higgs states or quiver invariants. We demonstrate how the refined Higgs index is naturally decomposed to a sum over partitions of the charge. We conjecture, and show in simple cases, that this decomposition expresses the Higgs index as a sum over a set of partition-induced Abelian quivers of the same total charge but generically of smaller rank. Unlike the previous approach inspired by a similar decomposition of the Coulomb index, our formulae compute the quiver invariants directly, and thus offer a self-complete routine for counting BPS states
Local Z2 scalar dark matter model confronting galactic GeV-scale γ -ray
We present a scalar dark matter (DM) model where DM ( XI ) is stabilized by a local Z2 symmetry originating from a spontaneously broken local dark U(1)X . Compared with the usual scalar DM with a global Z2 symmetry, the local Z2 model possesses three new extra fields, dark photon Z′ , dark Higgs ϕ and the excited partner of scalar DM ( XR ), with the kinetic mixing and Higgs portal interactions dictated by local dark gauge invariance. The resulting model can accommodate thermal relic density of scalar DM without conflict with the invisible Higgs branching ratio and the bounds from DM direct detections, thanks to the newly opened channels, XIXI→Z′Z′,ϕϕ . In particular, due to the new particles, the GeV scale γ -ray excess from the Galactic Center (GC) can be originated from the decay of dark Higgs boson which is produced in DM annihilations
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